A5024179610- Plant Water Relations and Carbon Dynamics
- Tree-ring climate responses
- Atmospheric and Environmental Gas Dynamics
- Plant responses to elevated CO2
- Forest ecology and management
- Meteorological Phenomena and Simulations
- Climate variability and models
- Wind and Air Flow Studies
- Hydrology and Watershed Management Studies
- Fluid Dynamics and Turbulent Flows
- Energy and Environment Impacts
- Irrigation Practices and Water Management
- Soil and Unsaturated Flow
- Fire effects on ecosystems
- Greenhouse Technology and Climate Control
- Environmental and biological studies
- Sustainability and Ecological Systems Analysis
- Solar Thermal and Photovoltaic Systems
- Aeolian processes and effects
- Hydrology and Sediment Transport Processes
- Soil Moisture and Remote Sensing
- Soil erosion and sediment transport
- Geophysics and Gravity Measurements
- Soil Carbon and Nitrogen Dynamics
- Ecosystem dynamics and resilience
Universidade de Brasília
2010-2025
Duke University
2001-2014
St Nicholas Hospital
2007
University of Lisbon
1994-1999
Instituto Politécnico de Lisboa
1994
The Moderate Resolution Spectroradiometer (MODIS) sensor has provided near real-time estimates of gross primary production (GPP) since March 2000. We compare four years (2000 to 2003) satellite-based calculations GPP with tower eddy CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> flux-based across diverse land cover types and climate regimes. examine the potential error contributions from meteorology, leaf area index (LAI)/fPAR,...
Torrefaction is a thermochemical pretreatment that enhances biomass properties, improving energy density, decomposition resistance, and hydrophobicity, making it viable alternative as biofuel. This study performed thermodynamic assessment of the torrefaction process for urban forest waste, integrating experimental data with two-step reaction kinetic modeling to evaluate product yields properties using Aspen Plus software. The was modeled yield reactor, employing Peng–Robinson equation...
We introduce an analytical model, the Wald long-distance dispersal (WALD) for estimating kernels of wind-dispersed seeds and their escape probability from canopy. The model is based on simplifications to well-established three-dimensional Lagrangian stochastic approaches turbulent scalar transport resulting in a two-parameter (or inverse Gaussian) distribution. Unlike commonly used phenomenological models, WALD's parameters can be estimated key factors affecting wind dispersal--wind...
Abstract We combined Eddy‐covariance measurements with a linear perturbation analysis to isolate the relative contribution of physical and biological drivers on evapotranspiration (ET) in three ecosystems representing two end‐members an intermediate stage successional gradient southeastern US (SE). The study ecosystems, abandoned agricultural field [old (OF)], early planted pine forest (PP), late‐successional hardwood (HW), exhibited differential sensitivity wide range climatic hydrologic...
In the southeastern United States (SE), conversion of abandoned agricultural land to forests is dominant feature land‐cover change. However, few attempts have been made quantify impact such on surface temperature. Here, this issue explored experimentally and analytically in three adjacent ecosystems (a grass‐covered old‐field, OF, a planted pine forest, PP, hardwood HW) representing successional chronosequence SE. The results showed that changes albedo alone can warm by 0.9°C for OF‐to‐PP...
Orthonormal wavelet transformation (OWT) is a computationally efficient technique for quantifying underlying frequencies in nonstationary and gap-infested time series, such as eddy-covariance-measured net ecosystem exchange of CO 2 (NEE).We employed OWT to analyze the frequency characteristics synchronously measured modeled NEE at adjacent pine (PP) hardwood (HW) ecosystems.Wavelet cospectral analysis showed that PP was more correlated light vapor pressure deficit daily scale, HW leaf area...
The spectrum of soil moisture content at scales ranging from 1 hour to 8 years is analyzed for a site whose hydrologic balance primarily governed by precipitation ( p ), and evapotranspiration (ET). uniformly planted loblolly pine stand situated in the southeastern United States characterized shallow rooting depth R L ) near‐impervious clay pan just below . In this setup, when ET linearly increases with increasing root zone (θ), an analytical model can be derived energy E s f where...
Estimation of water uptake by plants and subsequent stress are complicated the need to resolve soil‐plant hydrodynamics at scales ranging from millimeters meters. Using a simplified homogenization technique, three‐dimensional (3‐D) soil movement dynamics can be reduced solving two 1‐D coupled Richards' equations, one for radial toward rootlets (mesoscale, important diurnal cycle) second vertical motion (macroscale, relevant interstorm timescales). This approach allows explicit simulation...
Abstract Vegetation plays a central role in controlling terrestrial carbon (C) exchange, but quantifying its impacts on C cycling time scales of ecological succession is hindered by lack long‐term observations. The net ecosystem exchange (NEE) was measured for several years adjacent ecosystems that represent distinct phases the southeastern USA. experiment designed to isolate vegetation – apart from climate and soils biosphere–atmosphere fluxes CO 2 water vapor. NEE near zero over 5 at an...
Abstract The linkages between soil moisture dynamics and convection triggers, defined here as the first crossing boundary layer height (hBL) lifting condensation level (hLCL), are complicated by a large number of interacting processes occurring over wide range space time scales. To progress on this problem, soil–plant hydrodynamics model was coupled to simplified ABL budget explore feedback triggers. hydraulics formulation accounted mechanistically for features such root water uptake,...
The southeastern United States is experiencing a rapid regional increase in the ratio of pine to deciduous forest ecosystems at same time it changes climate. This study focused on exploring how these shifts will affect carbon sink capacity US forests, which we show here are among strongest sinks continental States. Using eight-year-long eddy covariance records collected above hardwood (HW) and plantation (PP) co-located North Carolina, USA, that net ecosystem exchange CO2 (NEE) was more...
A number of recent studies have attributed a large proportion soil respiration (R(soil)) to recently photoassimilated carbon (C). Time lags (tau(PR)) associated with these pulses photosynthesis and responses R(soil) been found on time scales hours weeks for different ecosystems, but most find evidence tau(PR) the order 1-5 d. We showed that such are commensurate CO(2) diffusion from roots surface, may thus be independent photosynthetic pulses. To further quantify role physical (i.e. edaphic)...
Abstract We compared four existing process‐based stand‐level models of varying complexity (physiological principles in predicting growth, photosynthesis and evapotranspiration, biogeochemical cycles, stand to ecosystem carbon evapotranspiration simulator) a new nested model with 4 years eddy‐covariance‐measured water vapor ( LE ) CO 2 Fc fluxes at maturing loblolly pine forest. The resolves the ‘fast’ H O exchange processes using canopy turbulence theories radiative transfer whereas slowly...
Abstract Using a combination of model simulations and detailed measurements at hierarchy scales conducted sandhills forest site, the effect fertilization on net ecosystem exchange ( NEE ) its components in 6‐year‐old Pinus taeda stands was quantified. The measurements, collected over 20‐d period September October, included gas eddy covariance fluxes, sampled for 10‐d each fertilized stand control stand. Respiration from floor above‐ground biomass measured using chambers during experiment....
The pathway to summertime convective precipitation remains a vexing research problem because of the nonlinear feedback between soil moisture content and atmosphere. Understanding this is important southeastern U. S. region, given high productivity timberland area role in maintaining productivity. Here we explore triggers for wide range states air relative humidity mosaic landscape primarily dominated by hardwood forests, pine plantations, abandoned old field grassland. Using half‐hourly...
Flow disturbances near tall forest edges are receiving significant attention in diverse disciplines including ecology, management, meteorology, and fluid mechanics. Current theories suggest that a edge, when the flow originates from into large clearing, retains its canopy turbulence structure at exit point. Here, we propose this framework is not sufficiently general for dense forested shares several attributes with backward-facing step (BFS) flow. Similar analogies, such as rotor-like...